Transcript Chapter 34 Vertebrates

BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
Chapter 34
Vertebrates
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
VERTEBRATES
• Most chordates
are vertebrates:
have a segmented
backbone
Vertebrae
Backbone
Skull
– Their
endoskeletons
include a skull
– Their backbone
is composed of
vertebrae
Figure 18.16
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18.17 Most vertebrates have hinged jaws
• Lampreys lack hinged jaws
– They are classified as agnathans
• Jaws evolved by
the modification
of skeletal
supports of the
gill slits
Gill
slits
Skeletal
rods
Skull
Mouth
Figure 18.17A, B
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5 Main Classes of Vertebrates
• Fish
• Amphibians
• Reptiles
• Birds
• Mammals
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Fish
• Fish are jawed vertebrates with gills and paired
fins
• There are two classes of fish
– Chondrichthyes, cartilaginous fishes such as
sharks and rays. They have a lateral line system,
a sense organ used to detect vibrations.
– Osteichthyes, bony fishes such as tuna and trout
Figure 18.18A
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• Bony fishes are more diverse and have
– more mobile fins
– operculi that move water over the gills
– a buoyant swim bladder
BONY SKELETON
OPERCULUM
Gills
SWIM BLADDER
Figure 18.18B
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• There are three major classes of bony fishes
– Ray-finned
fishes
(salmon and
trout)
Rainbow trout,
a ray-fin
– Lobe-finned
fishes
(coelocanth)
– Lungfishes
(evolved into
humans)
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Coelacanth,
a lobe-fin
Figure 18.18C
18.19 Amphibians
• Amphibians were the first land vertebrates
• Class Amphibia is represented today by
– frogs
– toads
– salamanders
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– Their 4 limbs (tetrapods)
allow them to move on land
– However, amphibian larvae
must develop in water (and
go through metamorphosis)
– Found in damp habitats
– Threatened by fungal
pathogens, habitat loss, acid
rain, and pollution
Figure 18.19A-C
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18.20 Reptiles
• Class Reptilia is able to live
on land due to
– waterproof scales
– a shelled, amniotic egg
• Modern reptiles are
ectotherms (cold blooded)
– They warm their bodies by
absorbing heat from the
environment
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Figure 18.20A, B
Reptiles
• Include turtles, alligators, crocodiles, lizards,
and snakes
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• Dinosaurs were the most diverse reptiles to
inhabit land
– This group included some of the largest land animals
ever
– They may have been endothermic, producing their own
body heat
– They evolved into birds and some modern reptiles
Figure 18.20C
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18.21 Birds
• Like reptiles, class
Aves has
Teeth
(like reptile)
Wing claw
(like reptile)
– scales
– amniotic eggs
– No bladders
– Only one ovary
– Light bones
– Wings and feathers
Feathers
Long tail with
many vertebrae
(like reptile)
Figure 18.21A
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• Other bird characteristics include
– an endothermic
metabolism
– hollow bones
– a highly efficient
circulatory system
– A 4 chambered heart
Figure 18.21B, C
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18.22 Mammals
• Class Mammalia descended from reptiles
• Mammals are endothermic (warm blooded)
• There are two unique mammalian
characteristics
– Hair, which insulates the body
– Mammary glands, which produce milk that
nourishes their young
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• Most mammals give birth to young after a
period of embryonic development inside the
body of the mother
– The embryo is nurtured by an organ called the
placenta
• A few mammals
lay eggs-Monotremes
• Platypus
• Echidna
Figure 18.22A
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• Marsupials have a
short gestation
– The tiny offspring
complete
development inside a
pouch
– Example: kangaroos,
koalas, wombats,
Tasmanian devils
Figure 18.22B
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• Most mammals are eutherians, also called
placentals
– They have a relatively
long gestation
– Complete embryonic
development occurs
within the mother, in a
sac called a placenta
Figure 18.22C
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